Turbochargers, and less, commonly, superchargers, are used to increase engine power output by providing higher charge-air density such that more fuel can be burned in each engine cycle, by scavenging airflow to clear the cylinders of combustion products, and by cooling engine parts allowing for power increases. The utilization of a turbocharger with an engine results in increased horsepower output and higher brake mean effective pressure because the higher air density improves engine performance at low loads and permits the engine to operate not only at an optimum efficiency point, but also at reduced speeds and loads. The use of a turbocharger may further act to restore sea level ratings on engines operating at high altitudes by compensating for reduced atmospheric pressures, and may make possible maximum speed acceleration to synchronous speed for fast reliable starts as well as reducing fuel and oil consumption.
Turbocharger and supercharger compressors are very finely machined and run at very high speeds, generally many thousands of revolutions per minute, and therefore are very sensitive to deposit deposition. These deposits are especially severe in engines equipped with exhaust gas recirculation (EGR) or where crankcase ventilation gases are fed into the intake system of the engine upstream of the compressor.
Previously, compressor deposits had to be removed by removing and dismantling the compressor and cleaning the parts away from the engine. One approach is to use chemical cleaning fluids to dissolve the deposits. One cannot simply spray cleaning fluid into the compressor with the engine turned off, however, as large amounts of cleaning fluid are required which will accumulate and cause puddles in the inlet system. The result of this is that these puddles will be ingested and the engine will “run away” when the engine is turned back on, possibly resulting in dangerous operating conditions and damage to the engine. For the same reason, one cannot imply spray cleaning fluid into the compressor while the output of the compressor is fed into the operating engine. One potential solution to prevent “run away” under these conditions is to install an air restriction valve in the air intake system. However, this would entail significant engineering modification and does hot prevent the engine from consuming the cleaning fluid as a non-ideal fuel.
Surprisingly, we have discovered a method for removing turbocharger and supercharger compressor deposits without dismantling the compressor that allows for the cleaning of deposits on a running engine, but without the cleaning fluid being consumed by the engine. Removal of these deposits are important because excessive deposits can cause a restriction of intake airflow, loss of compression, loss of power in the engine, and increased emissions, especially smoke.